component
TD8655
Public Made by Adomby adom
Techcode Semicon DC-DC Converters, QFN-20-EP(4x4). Pinout cross-checked by two models against the datasheet, KiCad symbol/footprint/3D.
3D Model
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Symbol & Footprint
Schematic Symbol
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PCB Footprint
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Datasheet
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README
markdownTD8655
Techcode Semicon · DC-DC Converters · QFN-20-EP(4x4)
TD8655 from Techcode Semicon, in a QFN-20-EP(4x4). Pinout and pin descriptions extracted from the manufacturer datasheet (extract_pins, cross-checked by a second model); symbol, footprint, and 3D from KiCad-official CAD.
Pinout
| Pin | Name | Type | Function |
|---|---|---|---|
| 1 | BST | power_out | Internal high-side driver power bias, typically 5.4V above VIN, with a typical 0.1uF capacitor connected between BST and SW. |
| 2 | VIN | power_in | Supply input, recommended 9V to 40V with absolute maximum rating of -0.3 to +43V. |
| 3 | ISENSE | input | Input current sense; absolute maximum rating ISENSE to VIN is -0.3 to +0.3 V. |
| 4 | COMP | passive | Error amplifier output where the converter stability compensation network is placed; absolute maximum rating to GND is -0.3 to +6 V. |
| 5 | FREQ | input | Switching frequency setting: a 120k to 30k ohm resistor to GND sets FSW=12000k/RF, and a floating pin gives 200kHz. |
| 6 | FB | input | Feedback input referenced to 1.20V (VFB), set by a resistor divider between VOUT and GND; absolute maximum rating -0.3 to +6 V. |
| 7 | EN | input | On/off control pin; electrical characteristics are specified with EN=3V. |
| 8 | ISET | input | Sets the output constant-current level, with VISET = 1.2V x (R18/(R18+R19)); absolute maximum rating -0.3 to +6 V. |
| 9 | COUT1 | input | Current limit of the 1st output; threshold voltage is 108mV across the sense resistor RCS1 (IOC = 108mV/RCS). |
| 10 | COUT2 | input | Current limit of the 2nd output; threshold voltage is 108mV across the sense resistor RCS2 (IOC = 108mV/RCS). |
| 11 | COUT3 | input | Current limit of the 3rd output; threshold voltage is 108mV across the sense resistor RCS3 (IOC = 108mV/RCS). |
| 12 | COUT4 | input | Current limit of the 4th output; threshold voltage is 108mV across the sense resistor RCS4 (IOC = 108mV/RCS); absolute maximum rating to GND is -0.3 to +0.3 V. |
| 13 | CS34 | input | Pull low to disable the COUT3/COUT4 constant-current function, and high to enable it. |
| 14 | SS | passive | Soft-start pin; a capacitor is connected between this pin and GND (typical soft-start time 10 ms with CSS = 0.1uF). |
| 15 | TS | passive | Test pin; the datasheet gives no functional description or connection requirement. |
| 16 | GND | power_in | Ground pin. |
| 17 | LSD | output | Low-side driver output for the external low-side power NMOS in the synchronous configuration. |
| 18 | VDD | power_out | Internal 5.4V power supply; a 1uF (or more) capacitor is connected between this pin and GND. |
| 19 | SW | passive | Inductor terminal (switch node); absolute maximum rating SW to GND is -0.3 to VIN+0.6 V. |
| 20 | HSD | output | High-side driver output for the external high-side power NMOS in the synchronous configuration. |
| 21 | EP | passive | Exposed pad (from the footprint; not named in the datasheet pin table). |
Key specifications
| Parameter | Value |
|---|---|
| Manufacturer | Techcode Semicon |
| Package | QFN-20-EP(4x4) |
| Category | Power Management (PMIC) |
| Pins | 21 |
Electrical characteristics
Limits as printed in the datasheet (page.json metadata.characteristics carries them as data).
| Parameter | Symbol | Min | Typ | Max | Unit | Conditions | Page |
|---|---|---|---|---|---|---|---|
| VIN Supply Voltage | VIN | 9 | 40 | V | 4 | ||
| IIN Supply Input Current | IIN | 0.5 | 1.5 | 3 | mA | EN=3V, Vout=5V,No load | 4 |
| VIN UVLO Turn ON | VUP | 8.2 | 8.5 | 8.9 | V | VIN Rising | 4 |
| Feedback voltage | VFB | 1.176 | 1.2 | 1.224 | V | VEN=3V | 4 |
| Feedback voltage Tolerance | -2 | 2 | % | 4 | |||
| Switch frequency | FSW | 170 | 200 | 230 | KHz | RFREQ=60Kohm | 4 |
| Duty cycle | D | 95 | % | 4 | |||
| OCP threshold | VTOCP | 100 | 108 | 116 | mV | 4 | |
| ISNESE to VIN | -0.3 | 0.3 | V | 3 | |||
| VIN Supply Input Voltage | VIN | -0.3 | 43 | V | 3 | ||
| BS to SW | -0.3 | 6 | V | 3 | |||
| SW to GND | -0.3 | V | 3 | ||||
| BS to GND | -0.3 | V | 3 | ||||
| VFB,ISET,COMP,LSD,FREQ,SS CS34,TS to GND | -0.3 | 6 | V | 3 | |||
| COUT1-4 to GND | -0.3 | 0.3 | V | 3 | |||
| Thermal Resistance from Junction to ambient | θJA | 40 | ºC/W | 3 | |||
| VIN Supply Voltage | VIN | 9 | 40 | V | 4 | ||
| Output voltage range | VOUT | 1.2 | 28 | V | 4 | ||
| Output current range | IOUT | 20 | A | 4 | |||
| Operating Temperature | -40 | 85 | ºC | 4 | |||
| Storage Temperature Range | TSTG | -60 | 150 | ºC | 4 | ||
| Maximum Lead Soldering Temperature | TSDR | 260 | ºC | 10 Seconds | 4 |
CAD (KiCad official)
- Symbol:
TD8655 - Footprint:
Package_DFN_QFN:QFN-20-1EP_4x4mm_P0.5mm_EP2.5x2.5mm - 3D model: QFN-20-EP(4x4) (KiCad packages3D, STEP)
- 3D model files:
td8655-etched.step/td8655-etched.glbcarry the MPN laser-etched on the die in a toggleableAdom.LaserEtchgroup (Fusion-ready);td8655.step/td8655.glbare the bare package body.
Provenance
Data extracted from the manufacturer datasheet, not a distributor listing:
- Datasheet: Techcode Semicon datasheet (12 pp, sha256
85d02fd146ba7500, retrieved 2026-10-20, tier: lcsc) - Extractor: parts-factory
2.0.0/extract_pins 0.3, primaryclaude-haiku-5-5(text), consensusclaude-sonnet-5-5(agreed), guards: pin_guards 0.1: passed. Pins are checked against the footprint pad set and their cited datasheet pages before publish. - CAD: KiCad official libraries (CC-BY-SA 4.0).